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The Zero-Emissions Tug

What was once a dream is fast becoming a reality.

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The Damen RSD-E tug design (illustration courtesy Damen)

By A.J. Pessa 01-24-2020 11:48:00

(Article originally published in Sept/Oct 2019 edition.)

With a request for a full-sized, battery-propelled, all-electric tugboat, Ports of Auckland was thought to be “dreaming.” And you might say a dream team was founded when the Netherlands-based Damen Group agreed that the request was feasible from a business perspective. Yet these two parties signed a contract in July promising a battery-powered tug with a 2800 kWh energy rating and 70 tons of bollard pull – Damen’s RSD-E Tug 2513 – by 2021. It will be the first zero-emissions, fully electric shiphandling tug in the world.

The pioneering project comes one year after the Climate Leaders Coalition was launched in New Zealand. Ports of Auckland is among the 122 organizations in this coordinated effort to reduce carbon emissions in New Zealand. Tony Gibson, CEO, Ports of Auckland, attributes persistence and collaboration as essential for fighting climate change. “We have set ourselves the goal of being zero emission by 2040,” he says. “To meet this goal, we needed to find a zero emission option for our tugs.” 

Adds Allan D’Souza, Ports of Auckland’s General Manager for Marine, Engineering & General Wharf Operations: “When we first looked into buying an electric tug in 2016, there was nothing on the market. We are very happy with our existing Damen ASD Tug 2411, and we knew Damen were building hybrid tugs, so Damen was a logical choice for a partner when we wanted to look at the possibility of developing a fully electric model. Damen’s willingness to think differently and invest in the necessary research and development has been critical to the success of this project.” 

At this rate, New Zealand – and the Ports of Auckland – may well emerge as leaders in zero-emissions solutions. 

Collaborative Efforts

They’re not alone. A partnership in Japan has plans to develop a similar full-sized, zero-emissions tugboat with a bollard pull of 50 tons for ship-assist work in Tokyo Bay. At the center of this project is newly founded e5 Lab, tasked with providing a powertrain platform for this and other electric vessels. The creation of e5 Lab results from an agreement between Ashahi Tanker Co., Exeno Yamamizu Corporation, Mitsui OSK Lines and Mitsubishi Corporation. The e5 Lab harbor tugboat will be propelled primarily by battery and will be supported by hydrogen fuel cells and a single auxiliary generator – battery and hydrogen power in the same system.  

Mitsubishi says e5 Lab was formed to support the Japanese shipping industry by providing solutions for seven different challenges including electric propulsion, communications systems, sensor technology, ship-to-shore data and automation, standards for new technology and large capacity rechargeable batteries.

The battery-and-hydrogen-powered tugboat is still in an early phase and will include tugboat company Tokyo Kisen Co. to meet the delivery date of 2022. 

In Turkey, Navtek Naval Technologies and Corvus Energy have been developing a battery-powered harbor tug of 30 tons bollard pull and 1500 kWh energy rating. In development since 2018, Navtek's NV-712 ZeeTug (Zero Emissions Electric Tug) will utilize a Corvus Orca energy storage system (ESS) and have software from BMA technology. These digital aspects of the energy management system (EMS), or “brain” of the vessel, are key to developing workable battery-powered tugs. 

Navtek chose a fully electric design knowing that the tug would have specific and “narrow” duties, meaning predictable, and vessels with predictable duties are the best candidates for battery-powered systems. It’s what makes battery-powered ferries and passenger ships less complicated than tugs. 

While ferries and passenger ships repeat the same voyages daily, changing speed and other factors at predictable rates, tug operations are more versatile and frequently include higher-risk jobs, such as assisting large vessels. Having predictable downtime to charge the vessel's battery is another factor.

Results from this project may be visible before the end of the year as the vessel is due for delivery soon to the Port of Istanbul.

Vessel “Brains”

The future of tugboats and barges, especially battery-powered versions, is largely a matter of integrated software. Energy management systems (EMSs) function as the figurative “brains” of a modern vessel with ears, eyes and nose in the form of sensor technology and human-machine interfaces (HMIs). When an EMS is used to integrate diesel engines, battery power and other vital components on a vessel – such as data storage and automation – it can be termed an integrated system.

An integrated system for tugs and barges potentially includes using a touch screen monitor to gage and adjust variables of towing operations, such as winch tensions, heel angle, box coolers, oil pressure, cooling water temperatures, tank levels and anchor handling machinery. Improved preventative maintenance and avoiding unexpected downtime are other benefits.

The performance of these systems begins with having reliable technology to collect and deliver data. The next challenge is displaying that data in the wheelhouse, or other location, in a manner that is helpful. For these reasons, marine experts and computer nerds have never been in closer contact. 

Damen has been working with VanBerlo, a product developer, to focus on the “user experience” of its EMS. “User experience” is a familiar term to folks working in IT and is essentially a matter of making a computer easy to use. So optimizing a tugboat wheelhouse now requires the help of computer science professionals who have the skills to design a graphical user interface (GIF) to improve the user experience. 

To accomplish this, the computer nerds from VanBerlo visited a tug simulator and also sailed aboard a tug in the Port of Rotterdam.

Damen says its EMS research is about safety and providing more control to the vessel’s operators. It’s a growing field. According to a report released by Mordor Intelligence LLP in April, the global EMS market will grow at a compound annual rate of nearly 14 percent between 2019 and 2024. In 2018, the EMS market was valued at $25.88 billion. 

Major companies are involved including Wärtsilä and the Wärtsilä HY package, which it says is the only integrated hybrid power module in the maritime industry. Wärtsilä HY was installed on a tugboat for the first time on Gondan Shipbuilders’ escort tug Vilja, delivered in June. The Vilja is an ice-breaking tug with 100 tons of bollard pull and boasting smokeless operation. 

Wärtsilä HY optimizes diesel engines with battery power and features a “green mode” that is capable of zero-emissions – and does so with more bollard pull than any other solution. “This vessel is the most powerful tug operating with hybrid propulsion,” says Giulio Tirelli, Director of Sales & Business Intelligence, Wärtsilä Marine, “and it can be considered as creating a benchmark in the new era of modern shipping.”  

Retrofits

Breakthroughs in the performance and cost of batteries have encouraged marine companies to consider electric and hybrid options. Jay Edgar, Vice President of Engineering Services at Crowley Marine, says this is one reason Crowley is interested in these solutions for its tugboats: “In terms of an application, we’ve been working closely with our operations team to understand how and where those technologies can come into play.”

Across the industry, digitization and emissions reductions are most often taking place through retrofit projects. One example is the Goliah, a Crowley tug with 73 tons of bollard pull, operating in California. Goliah is a 1970s build that was repowered in 2017 and more recently upgraded with a cutting edge EMS from Bluefin Marine and Beijer Electronics. 

A priority of Crowley’s retrofit effort is to reduce emissions by upgrading its tug engines to meet EPA Tier IV requirements. Often these engine enhancements utilize urea-based SCR (selective catalytic reduction) technology. However, the difficulty of transporting urea makes GE Tier IV emission engines, a non-urea solution, an attractive alternative in some cases. 

The new K?pena Class tugboats for Young Brothers in Hawaii are the first to utilize these non-urea GE engines. A series of four was completed this year at the Conrad Shipyard in Amelia, Louisiana. The vessels were also among the first to be designed by Damen’s new U.S. branch. Damen’s Stan Tug 3711 model was specified for the project and is now offered as one of its standard builds. 

Meeting emissions standards with reliable solutions is paramount for tug and barge owners these days. In many cases, grant money is helping make this possible. It’s expected ports will act first to keep their emissions profiles ahead of regulatory standards. Creating a “greener” tug fleet obviously helps. 

Autonomous Tugs

Singapore – the world’s biggest port – is taking the lead in autonomous operations with the announcement in October that Keppel Smit Towage and ABB will jointly design tugs and barges that will be piloted remotely from shore. With approval from the American Bureau of Shipping, testing is expected to begin next year.     

It’s a logical extension of all the digital and EMS research going on. Remotely operated tugboats are more likely to be moving barges before assisting ships, and more of these types of projects will likely emerge in the next five years. Indeed, it’s all about dreams becoming reality. – MarEx  

Freelance writer Joey Pessa is a frequent contributor to The Maritime Executive.

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.